Method of degreasing raw wool



Patented Nov. 27, 1928.

- BUDOLF BRAUCKMEYEB, or eaunnnne r scnn'nsmn GERMANY.

METHOD OF DEGREASING RAW WOOL.-

No Drawing. Application filed January 14, 1926,

The invention relates to an improvement in or modification of the method of. degreasing raw wool described in the specification of the prior Patent No. 1,521,624.

Numerous suggestions have been made for the degre'asing of raw wool with the aid of organic solvents. The solvents suggested for the purpose, e. g; petrol, ether, carbondlsulhide, tetrachlorcarbon, and so on, are those which combine great degreasing capability with insolubility or poor solubility in water.

In contradistinction thereto a method is described inthe specification of the said prior patent according to which raw wool is degreased by means of a mild grease solvent, namely acetone, as a result of which the wool is degreased to an extent which leaves in the wool the valuable capillary fat of the fibres within desired limits.

The present invention is based on the recognition of the fact that in order to carry out the de-greasing of raw wool and the like, the

use ofwater soluble grease solvents is of con-,

siderable technical importance. In' consequence of the great area of the fibrous material and the great spreading power of the organic solvent, solvent are retained in the material after completion of the extraction process. Even after pressing the wool or subjecting it to centrifugal action, it contains in general more than 50% of its own weight in solvent. The removal of, the solvent retained by the wool and its reextraction presents considerable technical difficulties. In consequence of the poor heat conductivity of the wool for instance the supply of heat for evaporative purposes does not yield satisfactory results, while, for example, the passage therethrough of heated inert gases results-in the production of-very highly diluted mixtures which do not permit of economical re-extraction of the rease solvent, for instance'with the aid of a sorption liquids or solid adsorption media.

Moreover, it' has been observed that the freeing of the treated wool, from the solvent which is retained, by means of heat leads to injury of the fibres. S

The use of watersoluble grease solvents ofi'ers the great advantage that suchsolvents ,can be removed from the materialin the simplest possible. manner by] the use of water (or aqueous solutions). It glisted to remove insoluble grease solvents of 65 t e kind mentioned at the commencement of this specification by 'means of water, but in considerable quantities of the as already been sug-- Serial No. 81,324, and in Germany 19125, 1925.

eneral only the solvent on the surface of the bre is removed mechanically by the water,

while more or less large quantities of the solvent remain within the fibres.

It has now been found to be of very great importance to treat the degreased fibre with water under such conditions that, on the'one hand, the organic solvent is removed from within the fibre, and, on the other hand, a certain amount of water is'taken up by the fibre. Experiments have shown that in using water-soluble solvents by simply washing or flushing the degreased wool with the water the solvent present therein is wholly removed, and at the same time water penetrates the interior of the fibre. Organic solvents more diflicultly soluble in water, forexample, those which are soluble only in the ratio 1 to 10,.or 2 to 10, in water, also comewith in thescope of the present invention.

Moreover, the water soluble grease solvents to be used in accordance with the present invention and of whichmethyl alcohol is a type, in consequence of their mild actioncompared with the solvents hitherto used, such as petrol. benzol or the like, afford the advantage already referred to in the specification of the prior patent, that the degreasing oper-' ation may be carried out in a regulatable manner by which the valuable capillary fat is retained in the'fibres in greater or smaller quantities. p

In the specification of the saidprior patent it has been indicated as a very desirable result to be sought that a fat content of about 2 to 5% should be retained in the fibres; It has now been found that degreasing can be carried furtherwithout danger which, of course, is of advantage for subsequent d eing of the fibres, if ,in the treatment of the bres by water following on the extraction opportunity is afiorded to .the fibre to take up a certain amount. of water by absorption, so as to relace the fat removed. As a result the fibre is protected against damage. even if the degreasing is carried further.

In the treatment of degreased wool with water the water-soluble potassium salts and potassium soaps are also extracted. The washing water containing the potassium compound may be used in vthe usual manner, for example, may be dried to provide potashes or may be used for other fpurposes. Finally, treatment with water 0 the degreased wool offers the advantage that the I -ty constituents present, in the wool are found ver adva-nta eous' to free fromwater the raw Wool to be degreased, which enerally contains 15 to 20% moisture be ore it is treated with solvent, for example, in such manner as tolower the water content of the Wool to about 2 to 3%. Preferably the Water is removed by careful heating, for example, by means of hot air. As a result the wool fat hanging in lumps on the fibre is melted so that it is spread uniformly over the fibrous material. In the subsequent extraction, in the first place the fat on the surface of the fibre is removed, while the capillary fat, which favourably affects the elasticity of the fibres, is retained. Moreover, by the removal of the Water from the Wool prior to the extraction of the fat, the solvent action of the solvent is increased and a uniform degreasing of the wool ensured. I

Finally, by the removal of the waterfrom the wool the advantage is obtained that the potassium salts and soaps do not pass into solution during'the extraction of the fat, so

that after completion of the extraction proc-' ess the latter can be removed and rendered suitable for further use, for example, by treatment to provide potashes.

It has also been found that the method of degreasing Wool with the aid of mild watersoluble grease solvents canbe applied with.

advantage to the degreasing of Waste Wool containing fat or mineral oil, as also for the removal of spinning oil from yarns and fabricsf Also in such circumstances preliminary removal of Water and the treatment of the degreased material with water are to be recommended.

Claims:

1. Method of degreasing raw Wool consisting in primarily freeing the wool from Water leaving about 2 to 3% moisture in the wool, then treating the wool with water-soluble mild grease solvent.

2. Method of degreasing raw wool consisting in primarily freeing the .wool from water leaving about 2 to 3% moisture in the Wool. then treating the Wool with methyl 7 alcohol.

In testimony whereof Iaffix my signature.

RUDOLF BRAUCKMEYER. 

